Device for insuring uniform pressure upon explosive charges



' April 14, 1925. 1,533,406

V B. GROTTA DEVICE FOR INSURING UNIFORM PRESSURE UPON EXPLOSIVE CHARGESFiled Dec. a,' 1924 Fr; e.

5 moan-Yo r BENNETT GRQTTA Patented Apr. 14, 1925.

BENNETT sno'r'ra, on :r Me U-A, EENNSLVA=NIA, as'smnon no ATLAS -P.OWDERCOMPANY, or -WILMINGTON,.DELiWABLEFA,GOBPOEATIONROEDELAWABE.

DEVICE FOR mscame UNIFORM ranssnnn unon nxnnos arn,cnanens.

Application filed December 6, 1924. -Seriav1fNo.-754f,-353.

To all whom it may concern Be it known that BENNETT'GROMTA, citizen ofthe United States, residing at T'ainaqua, in the county of Schuylkilland State of Pennsylvania, have invented certain new and usefulImprovements in De vices 'for Tnsuring Uniform Pressure Upon ExplosiveCharges, of whiclrthe following is a specification.

My invention relates to an improvement in equipment commonly usedfor'the manu facture of detonators and other articles which aresimilarlyassembled and it has for its primary object the provision of improvedmeans for insuring uniform pres sure upon the explosive charges of suchdetonators.

In the manufacture of detonators 1t 1s cus'tomaryito deposit theexplosive charge used into a large number of detonator shells or metalcasings in a single operation, and then remove the rack contalning thecharged shells to a press where pressure length punches, all charges arethus compressed to a uniform height.

-It is a well nnown fact that by any of the methods which may beemployed commercially an exactly uniform weight of charge cannot bedeposited into the detonator shells. "This is due to the fact that thecharges are measured out byfirst filling a series of holes of theapproximate cubical content desired, with the explosive used, and thenpermitting this charge to -,fall into the shells. Variations in-tlensitycram explosive as well as variations in its flowing properties render itimpossible to deliver charges of exactly uniform weight. As aconsequence, with the usual methods of pressing, the under-weightcharges are under-pressed while the over-weight charges areover-pressed.

The over-pressed charges may result in distorted and bulged detonatorshells and there is also the possibility of rendering the chargenon-explosive by over-compressing, as for example, dead-pressecfulminate charges. On theother hand, under-pressed charges are conduciveto even greater ills,

stitutes a hazard in itself; "Furthermore 'the possib lity of fdetomtjors 'l'from. which part or all of the explosive charge has been ilost, beii'i'g" used {for initiating .61"- {otherexplosivcs,may resultinthe Wll known dangerous an'd'cost-ly mi'sfires.

difter extensive experimentation l have found that the above pressingdiific ilties maybe obi iatedby the'v'ery simpleidevic e which'is thesubject of this patent applicatioil. I a

I have found that by providing .a rack for the detonator shells which isso constructed "that l the g-shells are supported some *-resi'lie1itmaterial, such as rubber, which, in turn, is supported 'by a solidbacking, the pressure is eqi'ialized and charges tend to be uniformlycompressed.

One en'ibodiment' of my; invention {is illustrated in the {accompanyingdrawings, wherein Figure 1 is a perspective View of a "rack constructedin accordance with the invention,

Figure .2 is a horizontal sectional view illustrating the bottom plateplan,

FigureBis a perspectivewiew ofza modi- "fiedform of .bottomfpl'ate, and

Figures 4, '5, .'an'd-'- '6 are fragmentary .Qsectional views through"the recessed pojrti'ons bottom" plates, "like those illustrated in and6 each have a plurality of alined openings 8 formed therein throughwhich the detonator shells pass, with their closed ends disposeddownwardly. These closed ends rest upon a sheet of rubber, or likeresilient material, indicated at 9, and in order to se- .for example, asthe provision of spacing blocks or lugs 11 at the corners of the plates.Instead of utilizing a single sheet of resilient material as illustratedin Figures 1 and 2, to receive the lower ends of all of the detonatorshells in the rack, I may employ an individual resilient backing foreach deto-v nator. This may be accomplished as indicated in Figure 3,wherein a plate 7 corresponding to the plate 7, is provided with aplurality of recesses 12 corresponding in number to the] openings formedin plates 5 and 6. These recesses 12 in plate 7 are somewhat larger inarea than the bases of 'the detonators to be received therein, and

these recesses receive the resilient material indicated at 13, 14k and15 in Figures 3, 4, 5

and 6, respectively. In Figures 3 and 4, the recesses are illustrated ashaving straight sidewalls. In Figure 5 the recess which has beendesignated 12 is indicated as being of concave formation, while inFigure 6 the recess which has been designated 12 is indicated as beingof undercut formation in cross section It is, of course, obviousthat'the closed end of the detonator'shells will be supported by theresilient material in the bottom of the rack. weight charges receive thedesired degree of compression the detonator shells containing thesecharges will tend to recede while the under-weight charges will still besupported by the resilient backing. Inthis manner the over-weight chargeis not over-pressed and the under-weight charge is not underpressed. 4

I have found that by employing rack equipped with a sheet of rubberone-eighth inch thick, detonators having a variation of as much as 20%in weight'of charge may be i ture in the presence of two witnesses.

satisfactorily compressed with a single press. I have also found thatthe desired effect may be obtained by employing various resilientmaterials of different composition U .and thickness. The resilientmaterial may It is also apparent that as the overbe cemented orvulcanized to the solid backing of the rack, or it may be left loose.

WVhile I have described specifically how my invention may be applied inthe manufacture of detonators it is apparent that it would have asimilar application in the charging of any other explosive devicewherein the density or compression of the explosive charge is animportant factor. Therefore, the employment of a resilient backing inthe charging and pressing of any explosive into any type of shell orcasing must be considered within the scope of my invention.

Having described my invention, what I claim is:

1. A device used in the pressing of explosive charges into shells, orother containers, consisting of a rack for supporting the containers ina suitable position and a resilient backing on which the closed ends ofthe containers rest;

2. A. device for equalizing the pressure applied to several detonatorcompositions by a single press, which consists of a suitable rack fittedwith a resilient backing on which the detonator shells are placed.

3. A device for equalizing the pressure applied to several detonatorcompositions by a single press which consistsof a suitable rack fittedwith a backing of rubber on,

which detonator shells are placed.

4. A device for equalizing the pressure applied to several detonatorcompositions by a single press, which consists of'a suitable rackequipped with an individual backing .of

rubber of suitable resiliency for each detonator. a I

5; A device for equalizing the pressure applied to several explosivecharges, which consists of a support and guide for a pl u rality ofcontainers of the explosive charges and means yieldable beyond apredetermined pressure, upon which the ends ofsaid containers rest.

In testimony whereof he affixes his signa- BENNETT GROTTA. Witnesses Vv,

R. L. HI L, R. M. CooK.

